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Variable Legionella Response to Building Occupancy Patterns and Precautionary Flushing

When stay-at-home orders were issued to slow the spread of COVID-19, building occupancy (and water demand) was drastically decreased in many buildings. There was concern that widespread low water demand may cause unprecedented Legionella occurrence and Legionnaires’ disease incidence. In lieu of evi...

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Autores principales: Rhoads, William J., Sindelar, Meril, Margot, Céline, Graf, Nadine, Hammes, Frederik
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8950775/
https://www.ncbi.nlm.nih.gov/pubmed/35336130
http://dx.doi.org/10.3390/microorganisms10030555
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author Rhoads, William J.
Sindelar, Meril
Margot, Céline
Graf, Nadine
Hammes, Frederik
author_facet Rhoads, William J.
Sindelar, Meril
Margot, Céline
Graf, Nadine
Hammes, Frederik
author_sort Rhoads, William J.
collection PubMed
description When stay-at-home orders were issued to slow the spread of COVID-19, building occupancy (and water demand) was drastically decreased in many buildings. There was concern that widespread low water demand may cause unprecedented Legionella occurrence and Legionnaires’ disease incidence. In lieu of evidenced-based guidance, many people flushed their water systems as a preventative measure, using highly variable practices. Here, we present field-scale research from a building before, during, and after periods of low occupancy, and controlled stagnation experiments. We document no change, a > 4-log increase, and a > 1.5-log decrease of L. pneumophila during 3- to 7-week periods of low water demand. L. pneumophila increased by > 1-log after precautionary flushing prior to reoccupancy, which was repeated in controlled boiler flushing experiments. These results demonstrate that the impact of low water demand (colloquially called stagnation) is not as straight forward as is generally assumed, and that some flushing practices have potential unintended consequences. In particular, stagnation must be considered in context with other Legionella growth factors like temperature and flow profiles. Boiler flushing practices that dramatically increase the flow rate and rapidly deplete boiler temperature may mobilize Legionella present in biofilms and sediment.
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spelling pubmed-89507752022-03-26 Variable Legionella Response to Building Occupancy Patterns and Precautionary Flushing Rhoads, William J. Sindelar, Meril Margot, Céline Graf, Nadine Hammes, Frederik Microorganisms Article When stay-at-home orders were issued to slow the spread of COVID-19, building occupancy (and water demand) was drastically decreased in many buildings. There was concern that widespread low water demand may cause unprecedented Legionella occurrence and Legionnaires’ disease incidence. In lieu of evidenced-based guidance, many people flushed their water systems as a preventative measure, using highly variable practices. Here, we present field-scale research from a building before, during, and after periods of low occupancy, and controlled stagnation experiments. We document no change, a > 4-log increase, and a > 1.5-log decrease of L. pneumophila during 3- to 7-week periods of low water demand. L. pneumophila increased by > 1-log after precautionary flushing prior to reoccupancy, which was repeated in controlled boiler flushing experiments. These results demonstrate that the impact of low water demand (colloquially called stagnation) is not as straight forward as is generally assumed, and that some flushing practices have potential unintended consequences. In particular, stagnation must be considered in context with other Legionella growth factors like temperature and flow profiles. Boiler flushing practices that dramatically increase the flow rate and rapidly deplete boiler temperature may mobilize Legionella present in biofilms and sediment. MDPI 2022-03-03 /pmc/articles/PMC8950775/ /pubmed/35336130 http://dx.doi.org/10.3390/microorganisms10030555 Text en © 2022 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Rhoads, William J.
Sindelar, Meril
Margot, Céline
Graf, Nadine
Hammes, Frederik
Variable Legionella Response to Building Occupancy Patterns and Precautionary Flushing
title Variable Legionella Response to Building Occupancy Patterns and Precautionary Flushing
title_full Variable Legionella Response to Building Occupancy Patterns and Precautionary Flushing
title_fullStr Variable Legionella Response to Building Occupancy Patterns and Precautionary Flushing
title_full_unstemmed Variable Legionella Response to Building Occupancy Patterns and Precautionary Flushing
title_short Variable Legionella Response to Building Occupancy Patterns and Precautionary Flushing
title_sort variable legionella response to building occupancy patterns and precautionary flushing
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8950775/
https://www.ncbi.nlm.nih.gov/pubmed/35336130
http://dx.doi.org/10.3390/microorganisms10030555
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